gecko-dev/gfx/layers/ipc/AutoOpenSurface.h
2012-07-12 05:51:58 -07:00

74 lines
2.1 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: sw=2 ts=8 et :
*/
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef mozilla_layers_AutoOpenSurface_h
#define mozilla_layers_AutoOpenSurface_h 1
#include "base/basictypes.h"
#include "gfxASurface.h"
#include "mozilla/layers/PLayers.h"
#include "ShadowLayers.h"
namespace mozilla {
namespace layers {
/**
* Some surface types can be fairly expensive to open. This helper
* tries to put off opening surfaces as long as it can, until
* ahsolutely necessary. And after being forced to open, it remembers
* the mapping so it doesn't need to be redone.
*/
class NS_STACK_CLASS AutoOpenSurface
{
public:
typedef gfxASurface::gfxContentType gfxContentType;
/** |aDescriptor| must be valid while AutoOpenSurface is
* in scope. */
AutoOpenSurface(OpenMode aMode, const SurfaceDescriptor& aDescriptor);
~AutoOpenSurface();
/**
* These helpers do not necessarily need to open the descriptor to
* return an answer.
*/
gfxContentType ContentType();
gfxIntSize Size();
/** This can't escape the scope of AutoOpenSurface. */
gfxASurface* Get();
/**
* This can't escape the scope of AutoOpenSurface.
*
* This method is currently just a convenience wrapper around
* gfxASurface::GetAsImageSurface() --- it returns a valid surface
* exactly when this->Get()->GetAsImageSurface() would. Clients
* that need guaranteed (fast) ImageSurfaces should allocate the
* underlying descriptor with capability MAP_AS_IMAGE_SURFACE, in
* which case this helper is guaranteed to succeed.
*/
gfxImageSurface* GetAsImage();
private:
SurfaceDescriptor mDescriptor;
nsRefPtr<gfxASurface> mSurface;
nsRefPtr<gfxImageSurface> mSurfaceAsImage;
OpenMode mMode;
AutoOpenSurface(const AutoOpenSurface&) MOZ_DELETE;
AutoOpenSurface& operator=(const AutoOpenSurface&) MOZ_DELETE;
};
} // namespace layers
} // namespace mozilla
#endif // ifndef mozilla_layers_AutoOpenSurface_h